Viessmann vitodens 111-w and Opentherm

[wg100]

Hi all,

I had a viessmann vitodens 111-w boiler installed earlier in the year. I've got a BDR91 linked to the boiler. It's only in this recent cold weather that the radiators have started coming on again. I've noticed that despite none of the radiators calling for heat that the boiler will be circulating warm water through the CH system. I"m not sure if this is a feature of the boiler weather compensation or not - I'm also wondering whether I need to replace the BDR-91 with an Opentherm bridge? Any advice gratefully received.

[Richard]

There is a detailed post on the 100 Series here - viewtopic.php?f=5&t=477